Color lamp with spectral filter around filament



Dec. 21, 1965 w. c. DAusER COLOR LAMP WITH SPECTRAL FILTER AROUNDFILAMENT Filed OCT.. 29, 1962 2 Sheets-Sheet 1 Dec. 21, 1965 w. c.DAusER 3,225,243

COLOR LAMP WITH SPECTRAL FILTER AROUND FILAMENT Filed oet. 29, 1962 2sheets-sheet z WQ@ M United States Patent 3,225,243 COLR LAMP WlTI-lSPECTRAL FILTER ARUUND FILAMENT William C. Danser, 458 Melody Lane,North Muskegon, Mich. Filed 0st. 29, 1962, Ser. No. 233,585 16 Claims.(Cl. S13-112) This invention relates to a lamp, and more particularly toa lamp having a controllable, variable color output with an infinitecolor range, and relates to a monocolor lamp cartridge.

According to present ligh-ting technology, light of a selected colorfrom a lamp is obtained by applying a suitable color filtering materialto the bulb surface or by arranging suitable filtering or spectralselector plates adjacent the bulb in the path of the ligh-t. Thesemethods, while often satisfactory, have definite limitations, including(l) the inability to faithfully produce and reproduce true colors, (2)the very limited number of colors which can be projected, (3) the almostcomplete lack of controllable color variation, (4) the bulkiness,complexity, and multiplicity of elements necessary for even a fewdifferent colors, and the great difficulty of projecting a compositelight formed of a plurality of combined primary colors on a single axis.

It is therefore an object of this invention to provide a lamp that iscapable in and of itself of projecting light of any color in aninfinitely variable manner over the entire visible light range.

It is another object of this invention to provide a lamp that isvariably controllable to project any selected color, and by a simpledial adjustment, to change color to any other selected color within aninfinite variation of visible light, and all from the same bulb. Itsoutput of color shades over the visible range can be altered within asecond. Yet, its exterior appears no different from a normal light bulb.It is small and compact. It can be readily plugged into or removed froma socket. No special skill is required to insert it, or to operate it.It provides true color shades. It can combine light to form a compositeof colors such as three primary colors, and moreover projects thecomposite color on an axis as needed, for example, for photographic orrelated purposes.

It is another object of this invention to provide a lamp capable ofinfinite color variation, where the colors may be accurately reproducedat any time. Therefore, the compact lamp is capable of repeatedlyprojecting the same color at any time, and consequently, is valuable inscientitic, theatrical, display, decorative and other elds.

lt is another object of this invention to provide a monocolor lampcartridge that is small, simple in structure, and capable of projectinga preselected color of any intensity desired. The cartridge isrelatively inexpensive and yet extremely useful. It fills atechnological gap by providing true color projection of any preselectedcolor within the visible range from a very small unit. lt can be coupledwith similar controlled cartridges of different colors to produceprimary colors in any proportion and thus enable variable production ofany known color, up to and including white.

It is another object of this invention to provide a small monocolorcartridge Ithat can be enclosed in a small translucent envelope andused, for example, as a christmas tree bulb, a decorative display bulbor in a dozen other uses.

These and other related objects of this invention Will be apparent uponstudying the following specification in conjunction with the drawings inwhich:

FIG. l is a side elevational sectional view of the novel cartridge;

FIG. 2 is a side elevational view of a lamp partially broken away toshow a plurality of cartridges therein;

FIG. 3 is an enlarged sectional view taken on plane III- III of FIG. 2;

FIG. 4 is a schematic diagram of a typical electrical circuitcontrolling the lamp in FIGS. 2 and 3;

FIG. 5 is an elevational view of a single cartridge bulb partiallybroken away; and

FIG. 6 is an elevational View of a modified single cartridge bulbpartially broken away.

Basically, the inventive cartridge to be enveloped in a lamp, either ingroups or singularly, comprises a source of light in the form of afilament, a multilm spectral selector mantle surrounding and uniformlyspaced from the source, and light ray restricting means limiting theangle of incidence of light from the source onto the mantle to provide aselected spectral color output. More specifically, the cartridgeincludes an elongated, ceramic support and restricting element, theouter surface portions of which lie in an imaginary cylinder, and havinga relatively narrow and deep helical groove along its length, a helicallight source filament along the bottom of the groove and adapted toproject light in a narrow projection angle range out between the wallsof the groove, and a multifilm spectral selector mantle around `theoutside of the element to transmit only selected light wave lengths forthe color desired. The elongated ceramic element may be specificallydefined as the surface generated about an axis by a V lying in a planeincluding the axis and revolving about the axis while movinglongitudinally along the axis. The multifilm spectral selector mantle ispreferably a coating on a cylindrical, translucent, and usuallytransparent tubing support such as glass or quartz. Three cartridgespreferably `produce primary colors in the envelopes in varyingintensities to provide a composite light output of any selected colorfrom the envelope.

Referring now specifically to the drawings, the novel cartridge itlessentially comprises a source of light, usually a tungsten filament 12adapted to be connected to electrical leads to emit ordinary white lightcomposed of all colors of the spectrum. The helical filament is wound ona filament support and light ray restrictor 14. A multifilm spectralselector mantle i6, usually in the form of a coating on a cylindricaltube 18 of pyrex glass or quartz surrounds the filament and support.Elongated support i4 has an axis extending through the center. The outeredge surface portions of the element fall in the cylinder defined by theinner cylindrical surface of glass tube 18. A narrow, relatively deephelical groove 20 is formed in element 14 with the walls being at anacute angle with respect to each other. Filament l2 is supported at thebottom of the groove on an arcuate surface formed by rounding the apexof the V-shaped groove. The surfaces of element i4 may be thought of asgenerated or engendered about the axis, by a V having a rounded point orbottom, lying in a plane including the axis, and revolved about the axiswhile moved longitudinally along the axis. The legs of the V form thewalls 22 which restrict the angle of incidence of light from thefilament unto the spectral selector coating 16. This acute angle isrelatively small, ordinarily a few degrees. Since the color emitted froma spectral selector coating varies markedly with the angle of incidenceof the light thereon, optimum results are obtained from a spectralselector having the light rays projected exactly perpendicular thereto.Since, however, no significant light ou-tput would result if the grooves20 were so restricted, a small angular range is purposely provided. Theangle is made small enough to have essentially no effect on the truecolor output, and yet large enough to obtain a useable light output.This causes the output color to be that caused by an incidence angle onthe coating equal to the average angle of incidence of the acute rangeselected for the cartridge. Thus, using presently available data onspectral selector films, and the average angle of incidence for thespecific acute angle of groove Ztl for the particular cartridgeinvolved, the output color of the cartridge can be readily determined.

It is to be understood that the multifilm spectral selector coatingcomprises a conventional plurality of films of selected metals appliedone directly upon the other without intermediate lters. Normally, up todifferent layers can be applied as deemed necessary, but the totalthickness is not more than about forty microinches. The coatings areusually of rare earth metals for the visible light range. Filmsordinarily used for control of light in the visible region are formed byvapor deposition using magnesium fiuoride, zinc sulfide, siliconmonoxide, titanium dioxide, cerium dioxide, and antimony trisulfide.These selectors have almost no absorption, and do not changecharacteristics even under high heating conditions, as is known. Thecoatings generally are of dielectric materials. The base materials forthe films are usually glass, borosilicate glass or quartz. If thecoating is applied to the exterior of the cylinder, the cylinder istransparent to assure passage of light at the proper angle of incidencefor the light rays on the spectral selector coating. If the coating isapplied to the interior of the cylinder, the tube may be translucent andnot necessarily transparent since the light will already have passedthrough `the spectral selector, so that subsequent diffraction of therays will not be significant to the operation. The terms transparent andtranslucent are intended according to their ordinary usage. T he lighttransmission characteristics required depend upon the necessity ofimpinging the light rays onto the spectral selector coating at theControlled angle of incidence range. It is believed unnecessary toexpand upon the technology of spectral selectors further. Additionaltechnology may be obtained from several sources including Bausch & Lomband Optical Coating Laboratories.

Particular multifilm selectors may be selected to produce any desiredcolor. They are intended to usually produce the primary colors red,green and blue which can be combined in one lamp in this invention. Theselectors `transmit only the desired spectral band width from the visualspectrum of about 400 to 700 millimicron wave length range, to producethe particular color needed. For example, currently the Bausch & Lombred selector is identified as 90-2-600 coupled with a 90-2-540. Thegreen is ordinarily 90-4-540 coupled with 90-2-500, and the blue is90-1-480 coupled with 90-1-540. In each case, the first numberidentifies the angle of incidence, i.e. the 90 optimum angle from whichthe novel cartridge departs just slightly. The second number is a designdesignation. The third number defines a functional wave length. If `thespectral selector has a single wave length cutoff which must be defined,this third number is the wave length in millimicrons at thetransmittance point on this cutoff. This, for example, holds true Vforthe blue multifilm selector which selects visible wave lengths at theblue end of the spectrum to the ultra-violet range. This holds true alsofor the red selector which selects wave lengths at the red end of thelspectrum to the infrared range. The green filter, on the other hand,selects wave lengths from the middle of the visible range, and possessestwo cutoffs. Its third identification number then refers to the wavelength at the center of the band transmitted. Ordinarily, when the filmsare deposited by vacuum deposition techniques, the coating material isplaced in a vacuum reactor and heated until either it evaporates orsublimes. It then is allowed to condense on the translucent tube 18.

The cartridge 1t) in FIG. l may be inserted directly in a small glassenvelope 13 about the size of a Christrnas tree bulb, for example asillustrated in FIGS. 5 and 6. The electrical leads 17 are connected tothe ends of filament 12 and to any suitable type of socket connector 15.The leads and cartridge are supported on a suitable glass column 19. Thebulb envelope is evacuated and usually filled with an inner atmospheresuch as nitrogen, iodine, or other suitable substance according toconventional practice with bulbs. The small, true-color bulb can servefor decorative purposes on Christmas trees or displays, etc.

Alternatively, a group of the novel cartridges may be mounted in alarger envelope 3f) such as an opal diffuser envelope having ahemispherical lower portion as on a conventional light bulb (see FIG.2). The cartridges 10 are all supported on a central support column 32extending down into the hemisperical portion of the bulb from the tubebase 34. The cartridges are grouped in a symmetrical pattern to producea uniform light output from the hemispherical portion of the bulb. Theopal hemispherical diffusor blends the primary color light componentsinto a single-color, output light having even illumination from thediffusor along the axis of the bulb and the hemispherical portionthereof. This result is especially advantageous for use of the bulb withphotographic enlarging and printing as mentioned hereinafter, since notonly is the color exactly controllable, but also the illumination iseven, the output is along the bulb axis without requiring the use ofadditional optical means, and the individual colors are all uniformlyblended and integrated. A preferred pattern is the radial, generallycircular pattern shown in FIG. 3. Independent leads 36 connect to theouter ends of the` cartridges. A larger, central, common lead 38 extendsthrough column 32 and connects to the inner ends of the filaments. Thisalso supports the cartridges. In the arrangement shown, the threeprimary colors, red, green and blue, are all represented by thecartridges. The coatings 16 are selected of appropriate spectralselector combinations to obtain the desired output color. Here there arethree cartridges for red, three for green, and three for blue spacedalternately around the symmetrical pattern. The three leads to the threered cartridges are connected together in the base 34, the three leads tothe green cartridges are connected together in the base, and similarlythe three blue leads are connected. The tube base 34 in this exemplarystructure is provided with four prongs, No. l being the return prongfrom common return lead 38, No. 2 being the prong electrically connectedto leads to the three red cartridges, No. 3 being the prong connected toleads to the three green cartridges, and No. 4 being the prongelectrically connected to leads to the three blue cartridges. Of course,there may be any number from 1 on up of the particular colors involved,but three are shown for illustration purposes. The bulb is noticeablysimple in construction. It is easy to use merely by inserting it into aplug. The plug will merely have sockets 1', 2', 3 and 4 (FIG. 4) toreceive the respective pins l, 2, 3, and 4 leading to the plurality ofcartridges.

If all of the cartridges are provided with substantially equalelectrical potential, the three primary colors can be combined toproduce pure white light output composed only of the three primarycolors and not colors in the spectrum. If, on the other hand, it isdesired to produce any other color shade within the entire visiblespectrum, either one or two of the three primary color cartridges can bevaried in output intensity. Varying the primary components varies thecomposite output. To do this, power leads 42 to socket 40 are providedwith three independent variable transformers 44, 46 and 48 to controlthe electrical input to red, green and blue cartridges, respectively. Byvarying the output voltage from the transformers to increase one or twoof the colors, the composite color can be easily and widely changed overthe entire visible range of the spectrum. Although the three most commonprimary colors of red, green, and blue are discussed most with respectto this invention,

any three colors which, when combined, can produce white light areintended as primary colors and are included within the broader aspectsof this invention. If the transformers are wound on a logarithmicpattern, the individual component output variation will be linear. Ifthe transformers are linearly wound, the output variation will `belogarithmic.

In operation, therefore, the cartridge may be enclosed in a -small bulbenvelope and supplied with electric power to produce a monocolored bulb.Alternatively, the cartridges can be placed in groups to provide avariable light source. With three primary colors in an envelopeapproximately the size of a conventional bulb, and with electricalsuitable outlets and controls for the respective independent filaments,a single bulb can be caused to vary in color over the entire visiblerange in an infinitely variable manner. The attractiveness of thisinvention for display, decorative, or scientific purposes, is only tooobvious. Any particular selected color may be easily reproduced bysimply recording the values on the respective variable transformers toachieve a particular color the first time. In uses such as photographicprinting and enlarging, any color may be projected on a single axis fromthe bulb without resorting to complex filtering techniques heretoforeused, or the use of optical focusing elements. It will be obvious tothose in the art, that a host of other uses, and a great number of otheradvantages could be cited within the principles taught. It will beobvious to those in the art that the particular construction shown mayperhaps be modified physically to `suit a particular situation, whileapplying the inventive principles set forth herein. It is believed thatthis lamp and cartridge form a basic invention, and therefore theillustrated structures, although depicting the preferred forms of theinvention are not to be limiting in nature, but illustrative thereof.The invention is to be limited only by the scope of the appended claimsand the reasonable equivalents thereto in view of the state of the art.

I claim:

1. A lamp cartridge comprising: a source of light; a multifilm spectralselector mantle surrounding and uniformly spaced from said source; andlight ray restricting means limiting the angle of incidence of lightfrom said source on to said mantle to provide a selected spectral coloroutput.

2. A lamp cartridge comprising: a filament adapted to be mounted in aninert atmosphere; a multifilm spectral selector mantle around saidfilament; and means limiting the angle of incidence of light rays fromsaid filament onto said mantle to provide a source of controlled coloroutput.

3. A lamp cartridge having a controlled spectral band emission,comprising: a filament arranged in an orderly pattern; a translucenthousing around said filament; a multifilm spectral selector coating onsaid housing adapted to pass a preselected -spectral light band; andlight ray alignment means supported by said housing for limiting theangle of incidence of light rays on said multifilm coating and therebyproviding a controlled color output.

4. A monocolor lamp cartridge comprising: a helical filament about anaxis; a support for said filament; helical means radiating from saidaxis and providing a limited angle range of light projection from saidfilament; and multifilm spectral selector means at the radiatedextremity of said helical means to pass only a selected spectral rangeof light to create a selected color output.

5. A monocolor lamp cartridge comprising: a filament wound in a helicalpattern on an elongated support having a central axis; a translucent,annular cylindrical tube spaced from said filament; a multifilm spectralselector coating on said tube; and helically-oriented, light raylimiting means radiating away from said axis and toward said tube andrestricting the light from said filament incident to said coating to aspecific small angular range to provide a controlled color output fromsaid tube.

6. A lamp cartridge comprising: an elongated element having surfacesengenedered about an axis by a V lying in a plane including the axis andrevolved about the axis while moved longitudinally along the axis; ahelical filament supported in the groove formed by the apex portion ofsaid V; the legs of said V and thereby the walls engendered therebybeing at a small predetermined acute angle to restrict the angular rangeof light radiated from said filament; and a cylindrical multifilmspectral selector mantle around said filament and surface creatingessentially a monocolor output from said restricted light.

7. A lamp cartridge comprising: an elongated ceramic element, the outersurface of which lies in an imaginary cylinder, and having a helicalgroove along its length; said groove being relatively narrow and deep; ahelical filament along the bottom of said groove and adapted to projectlight in a narrow projection angle range out between the walls of saidgroove; a light transmitting cylinder around said element; and amultifilm spectral selector coating -on said cylinder to select from.the light from said filament wave lengths to produce a preselectedcolor.

S. A lamp, comprising: an enclosing sealed envelope having electricalconnections; a plurality of cartridges in said envelope and connected torespective ones of said electrical connections; said cartridges eachhaving a multifilm spectral selector mantle adapted to select light of apreselected color from a source; a light source in each cartridge, andmeans restricting the angle of incidence of light from said source ontothe spectral selector mantle to provide a preselected output color.

9. A lamp, comprising: an enclosing sealed envelope having electricalconnections; a plurality of lamp cartridges in said envelope connectedto respective ones of said electrical connections; said cartridges eachhaving a filament wound in a helical pattern on a support along an axis;a translucent annular cylindrical tube spaced from said filament; amultifilm spectral selecting coating on said tube; andhelically-oriente-d, light ray limiting means radiating away from -saidaxis and toward said tube restricting the light from said filamentincident to said coating to a specific small angular range to provide acontrolled color output from said tube.

10. A lamp, comprising: an enclosing sealed envelope having electricalconnections; a plurality of lamp cartridges in said envelope andconnected to respective ones of said electrical connections; saidcartridges each having an elongated ceramic element, the outer surfaceof which lies in an imaginary cylinder, and having a helical groovealong its length; said groove being relatively narrow and deep; ahelical filament along the bottom of said groove and adapted to projectlight in a narrow projection angle range out between the walls of saidgroove; a light transmitting cylinder around said element; and amultitilm spectral selector coating on said cylinder to select specificwave lengths of light from said filament to produce a preselected coloroutput.

Il. A lamp, comprising: an enclosing sealed envelope having electricalconnections; a plurality of lamp cartridges in said envelope andconnected to respective ones of said electrical connections; saidcartridges each having an elongated element having a surface formedabout an axis by a V lying in a plane including the axis and revolvedabout the axis While moved longitudinally along the axis; a helicalfilament supported in the groove formed by the apex of said V; the legsof said V and thereby the walls engendered thereby being at a smallpredetermined acute angle to restrict the angular range of lightradiated from said filament; and a cylindrical multifilm spectralselector mantle around said filament and surface creatingh essentially amono-color output from said restricted ligl t.

12. A lamp, comprising: an enclosing sealed envelope having electricalconnections; a plurality of lamp cartridges in said envelope andconnected to respective ones of said electrical connections; saidcartridges each having a filament wound in a helical pattern on asupport along an axis; a transluc-ent, cylindrical tube spaced from saidfilament; different multifilm spectral selector coatings on said tubecausing a plurality of output colors; helicallyoriented, light raylimiting means radiating away from said axis and toward said tube andrestricting the light from said filament incident to said coatings to aspecific angular range to provide the controlled color from each tube;and a variable electrical input control means for cartridges ofdifferent colors enabling the composite overall lamp color to be variedby variation of the electrical input to different color cartridges.

13. A lamp, comprising: an enclosing sealed envelope having an inertatmosphere and electrical connections; a plurality ofsymmetrically-arranged lamp cartridges in said envelope and connected torespective ones of said electrical connections; said cartridges eachhaving an elongated ceramic support element, the outer surface of whichlies in an imaginary cylinder, and having a helical relatively narrowand deep V-shaped groove along its length; the walls of said groovebeing at a small acute angle; a helical filament along the bottom ofsaid groove and adapted to project light in a narrow projection anglerange out between the walls of said groove; a light transmittingcylinder around said element; multifilm spectral selector coatings onrespective cylinders to select pre determined wave lengths from saidlight from said filaments to form a plurality of preselected outputcolors; and a variable input electrical control means for cartridges ofdifferent colors enabling overall lamp output color variation byvariation of the components thereof.

14. A lamp, comprising: an enclosing envelope having electricalconnections; a plurality of lamp cartridges in said envelope andconnected to respective ones of said electrical connections; saidcartridges each having an elongated element having surfaces formed aboutan axis by a V lying in a plane including the axis and revolved aboutthe axis while moved longitudinally along the axis; a helical filamentsupported in the base of the groove formed by the point of said V; thelegs of said V and thereby the walls engendered thereby being at a smallpredetermined acute angle to restrict the angle range of light radiatedfrom said filament; a cylindrical multifilm spectral selector mantlearound said filament and surfaces selecting wave lengths to createessentially a monocolor from said restricted light; different cartridgeshaving diferent colors; and variable input control means for thecartridges of different colors enabling overall lamp color variation byvariation of the components thereof.

15. A lamp cartridge comprising: a source of light; a spectral selectormantle capa-ble of selecting a limited wave length range of light fromlight impinged thereon at a controlled angle of incidence thereto, andsurrounding and uniformly spaced from said source; and light rayrestricting means limiting the angle of incidence of light from saidsource on to said mantle to provide a selected color output.

16. A lamp, comprising: an enclosing sealed envelope having elect-ricalconnections; a plurality of cartridges in said envelope and connected torespective ones of said electrical connections; sa-id cartridges eachhaving a multifilm spectral selector mantle adapted to select light of apreselected color from a source; thereby providing different colors fromthe cartridges; a light source in each cartridge; means restricting theangle of incidence of light from said source onto the spectral selectormantle to provide a preselected output color; said cartridges beingarranged around an axis of light output; and hemispherical opal difiusormeans on said axis in the path of the output light of the differentcolors to blend lsaid colors into a single color output with evenillumination along said axis.

References Cited by the Examiner UNITED STATES PATENTS 1,649,975 ll/l927Parks 313-33 2,007,945 7/1935 Harding 313-271 X 2,097,679 11/1937Swanson 313-222 X 2,412,496 `12/1946 Dimmick 88--105 2,545,896 3/1951Pipkin 313-116 FOREIGN PATENTS 746,249 3/1933 France.

778,438 7/1957 Great Britain.

834,087 5/1960 Great Britain.

GEORGE N. WESTBY, Primary Examiner.

12. A LAMP, COMPRISING: AN ENCLOSING SEALED ENVELOPE HAVING ELECTRICALCONNECTIONS; A PLURALITY OF LAMP CARTRIDGES IN SAID ENVELOPE ANDCONNECTED TO RESPECTIVE ONES OF SAID ELECTRICAL CONNECTIONS; SAIDCARTRIDGES EACH HAVING A FILAMENT WOUND IN A HELICAL PATTERN ON ASUPPORT ALONG AN AXIS; A TRANSLUCENT, CYLINDRICAL TUBE SPACED FROM SAIDFILAMENT; DIFFERENT MULTIFILM SPECTRAL SELECTOR COATINGS ON SAID TUBECAUSING A PLURALITY OF OUTPUT COLORS; HELICALLYORIENTED, LIGHT RAYLIMITING MEANS RADIATING AWAY FROM SAID AXIS AND TOWARD SAID TUBE ANDRESTRICTING THE LIGHT FROM SAID FILAMENT INCIDENT TO SAID COATINGS TO ASPECIFIC ANGULAR RANGE TO PROVIDE THE CONTROLLED COLOR FROM EACH TUBE;AND A VARIABLE ELECTRICAL INPUT CONTROL MEANS FOR CARTRIDGES OFDIFFERENT COLORS ENABLING THE COMPOSITE OVERALL LAMP COLOR TO BE VARIEDBY VARIATION OF THE ELECTRICAL INPUT TO DIFFERENT COLOR CARTRIDGES.